* {
    margin: 0;
    padding: 0;
}
.box {
    height: 50px;
    background: #000;
}
.aaa {
    height: 50px;
    margin-left: 100px;
    align-items: center;
}
.aaa li {
    list-style: none;
    color: blue;
    float: left;
    width: 100px;
    font-size: 16px;
    text-align: center;
    line-height: 50px;
}